• 대한화학회지
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• 제63권6호
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• pp.453-458
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• 2019

Synthesis of ZnCo₂O₃ oxide is performed by sol-gel method via nitrate-citrate route. Powder X-ray diffraction (XRD) study shows monoclinic unit cell having lattice parameters: a = 5.721(1) Å, b = 8.073(2) Å, c = 5.670(1) Å, β = 93.221(8)°, space group P_2/m and Z = 4. Average crystallite sizes determined by Scherrer equation are the range ~14-32 nm, whereas SEM micrographs show nano-micro meter size particles formed in ZnCo₂O₃. Endothermic peak at ~798 K in the Differential scanning calorimetric (DSC) trace without weight loss could be due to structural transformation and the endothermic peak ~1143 K with weight loss is due to reversible loss of O₂ in air atmosphere. Energy Dispersive X-ray (EDX) analysis profile shows the presence of elements Zn, Co and O which indicates the purity of the sample. Magnetic measurements in the range of +12 kOe to -12 kOe at 10 K, 77 K, 120 K and at 300 K by PPMS-II Physical Property Measurement System (PPMS) shows hysteresis loops having very low values of the coercivity and retentivity which indicates the weakly ferromagnetic nature of the oxide. Observed X-band EPR isotropic lineshapes at 300 K and 77 K show positive g-shift at g_iso ~2.230 and g_iso ~2.217, respectively which is in agreement with the presence of paramagnetic site Co²⁺(3d⁷) in the oxide. DC conductivity value of 2.875 ×10^-8 S/cm indicates very weakly semiconducting nature of ZnCo₂O₃ at 300 K. DRS absorption bands ~357 nm, ~572 nm, ~619 nm and ~654 nm are due to the d-d transitions ⁴T_1g(⁴F)→²E_g(²G), ⁴T_1g(⁴F)→⁴T_1g(⁴P), ⁴T_1g(⁴F)→⁴A_2g(⁴F), ⁴T_1g(⁴F)→⁴T_2g(⁴F), respectively in octahedral ligand field around Co²⁺ ions. Direct band gap energy, E_g~ 1.5 eV in the oxide is obtained by extrapolating the linear part of the Tauc plot to the energy axis indicates fairly strong semiconducting nature of ZnCo₂O₃.

• 미술이론과 현장
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• 제2호
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• pp.169-190
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• 2004

The purpose of this article is to delve into the problems of originality of the artwork by examining issues of reproduction within the contemporary art market. In contemporary arts, especially in terms of art production and consumption, we can't overlook society and its economic structure and its connection with of capitalism. As the purity of art creation has turned into an exchange value, art, especially an object as artwork, has fallen into the status of production in an economic marketing system. Walter Benjamin mainly referred to that point in his thesis Das Kunstwerk im Zeitalter seiner technischen Reproduzierbarkeit, which originated the sociology of plastic arts. This thesis, published in 1936, traced how the artistic functions of photograph and movie had been changed through the social development. His main concerns were movie and photograph but what I am concentrating from his point of view, is that even in the field of plastic arts, the manufacture of reproduction has been practiced as a primary method within the social and political contexts and development. Though I am referring to this in the main body of this article, reproduction in contemporary art strongly needs a new definition since it has been spread all over like a newest virus, not only by collector's personal taste or hut also by commercial circulations of these reproductions to the public. This relates to Benjamin's argument about the value of an exhibition at a museum(Ausstellungswert). Since the function of an artwork has been one of cultural industry, the manufacturing of reproduction raises unexpected problems, such as, the originality of the artwork, the value of an exhibition at a museum, its achievement as documentary and as a territory of art criticism. In this point of view, I want to inquire into the value and criteria of an exhibition in contemporary art through the review of the definitions and the intrinsic attributes of reproduction. Somehow in a broad sense, the reproduction is a product coming out of representation or copy (replica) of an original art work or an model. Therefore, the problems it presents differ from the Simulacre, which is an image without an original one. In terms of the Meanings of reproduction, we can distinguish it as reproductions, copies, and productions. These types of reproductions are not the original artworks reflected by the creative intention of the artists. For example, a publishing company reproduced some of lithographs of Salvador Dali in the 1960s. They are commercial copies in the form of representation or reproduction with no artistic and creative intention of the artist. However, In despite of this theoretical basis, reproductions of the famous artists are still displayed without any verification for of the public's quest for the artworks. Moreover, many commercial companies that are planning to exhibit art works of the world-famous artists only for their profits keep trying to speak ill of and judging by the law the honest art critics' articles which discuss the true values of exhibition. If freedom of expression is one of the ideals of democracy, even the judgment of the originality of the artworks should be freely expressed.

• 한국잡초학회지
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• 제4권2호
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• pp.194-203
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• 1984

남부지방(南部地方) 맥후작대두단포장(麥後作大豆團場)의 잡초(雜草)를 방제(防除)하기 위하여 발생전토양처리제(發生前處理土壤處理劑)인 Alachlor와 metribuzin, 발생후경엽처리제(發生後莖葉處理劑)인 Acifluorfen과 Bentazon의 4약제(藥劑)를 4조합(組合)의 체계처리(體系處理)로 공시(供試)하여 적용가능성(適用可能性)을 검토(檢討)하였다. 시험(試驗)은 피와 바랭이가 우점(優占)하는 조건하(條件下)에서 수행(遂行)되었으며, 약제처리(藥劑處理)에 따른 작물약해(作物藥害)는 Metribuzin과 Acifluorfen에서 경미(輕微)한 정도(程度) 나타났으며 입묘(立苗) 및 생장(生長)에의 영향은 없는 것으로 나타났다. 각(各) 조합(組合)의 약제처리(藥劑處理)가 0.5~0.75kg/ha인 곳에서는 파종후(播種後) 60일(日)에 어느 체계(體系)에서도 만족스런 방제효과(防除效果)가 인정(認定)되었다. 제초효과면(除草效果面)(60 DAS) 에서의 체계처리(體系處理)된 약제간(藥劑間)의 상호작용성(相互作用性)은 Metribuzin보다 Alachlor 체계(體系)에서 뚜렷하였으며, 대체로 각(各) 약제(藥劑) 0.25~0.5kg/ha 범위(範圍)에서 협력적(協力的)인 효과(效果)를 나타내는 경향9傾向)이었다. 그러나 대두성숙기(大豆成熟期)의 작물생장량(作物生長量)과 수량(收量)을 조사(調査)한 결과(結果)로는 각(各) 약제(藥劑)의 0.75kg/ha 수준(水準)에서 처리효과(處理效果)가 향상(向上)되고 있었으며 Bentazon 보다는 Acifluorfen의 발생후경엽처리(發生後莖葉處理)에서 유의적(有意的)인 경향(傾向)이 있다. 이는 파종후(播種後) 60일(日) 이후(以後)의 토양잔유성제초효과(土壤殘留性除草效果) 및 이에 따른 잡초경합해(雜草競合害)의 차이(差異)에 따른 결과(結果)로 해석(解析)이 되었다.